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HomeMy WebLinkAboutNCS000546_Email RE Aluminum Values_20160812From: Georaoulias, Bethany To: Bennett, Bradley; Randall, Mike Subject: Aluminum and Plant Allen Date: Friday, August 12, 2016 3:04:49 PM Attachments: image002.pna Okay, I traced this down in my memory banks. Plant Allen's original application had reported one exceptionally high value for Aluminum from one of their outfalls—many orders of magnitude over the benchmark. It was also a real outlier (along with a huge TSS value that's probably unusual). Here's the record I have from an original staff report summary (from the first round of all these, back in 2011): 1. Analytical Monitoring Notes: Two outfalls were sampled as part of the NPDES stormwater application. These outfalls (SW008 and SW015) were sampled in 2009 for the NPDES wastewater permit renewal application (submitted December 2009), as part of a prior arrangement with DWQ. Because we have adopted a consistent stormwater permitting strategy for all power plants, SPU accepted these results without requiring samples from the other outfalls for the individual permit application. See application documents (Form 2F). SW008 [Drains area with rail lines that carry coal and limestone; gravel storage area for structural steel, cable, spare equipment, etc.]: COD levels were elevated (80 mg/1) but not above the 120 mg/I benchmark. There were low BOD levels (<2.0 mg/1) in the same sample, which suggests a larger amount of non-biodegradeable organic material. TSS levels were very high (1500 mg/1) above the 100 mg/I benchmark. Aluminum (27.0 mg/1), copper (0.058 mg/1), and zinc (0.32 mg/1) levels were also above benchmarks (of 0.75 mg/I, 0.007 mg/I, and 0.067 mg/I, respectively). Radioactive substances were also reported. There are no stormwater benchmarks for these substances, but there are water quality standards based on annual averages. The reviewer noted the level of alpha emitters was around 5 pCi/I greater than the standard of 15 pCi/I. No results reported for antimony, lead, or thallium. So after all the back and forth with these, I'd redone two newer drafts [remember all that? I'd like to forget.] Anyway, here's the second revised draft permit from May 2012. This is the one that got as far as the Notice stage, but may not have even made public notice before the brakes were put on all these (maybe the day the notice was supposed to run; I can't really remember.] Anyway, here's what I'd proposed specifically for that one outfall SW008: Table 1. Analytical Monitoring Requirements Discharge Characteristics Units Measurement Frequency1 Sample Type2 Sample Location3 Total Suspended Solids (TSS) mg/L semi-annual Grab SDO Chemical Oxygen Demand (COD) mg/L semi-annual Grab SDO Oil and Grease (O&G) mg/L semi-annual Grab SDO pH standard semi-annual Grab SDO Aluminum (AI), Total Recoverable4 mg/L semi-annua14 Grab SDO 008 4 mg/L 4 Grab SDO Copper (Cu), Total Recoverable semi-annual Total Nitrogen (TN) mg/L annual Grab SDO Total Phosphorus (TP) mg/L annual Grab SDO Total Rainfall S inches semi-annual Rain Gauge - Footnotes: 1 Measurement Frequency: Twice per year during a measureable storm event. Z Grab samples shall be collected within the first 30 minutes of discharge. 3 Sample Location: Samples shall be collected at each stormwater discharge outfall (SDO) unless representative outfall status (ROS) has been granted. A copy of the letter granting ROS shall be kept on site. 4 Monitoring for each of these parameters may be discontinued at every outfall where four (4) consecutive samples are below the benchmark concentration in Table 3 or below the higher Cu benchmark. 5 For each sampled measureable storm event, the total precipitation must be recorded. An on -site rain gauge or local rain gauge reading must be recorded. This permit never went any further, and I don't know whether Mike looked into what may have been going on with this outfall when he drafted the more recent permit last year. I do remember that I was skeptical about it being a big problem given such an usual number, but I thought some more samples could confirm. There was probably more sampling done for the newer applications anyway. So there you have it. N Bethany Georgoulias Environmental Engineer Stormwater Program, Division of Energy, Mineral, and Land Resources N.C. Department of Environmental Quality 919 807 6372 office bethany. georgoulias e ncdenr.gov 1612 Mail Service Center, Raleigh, NC 27699-1612 (mailing) 512 N. Salisbury Street, Raleigh, NC 27604 (location) Website: hhhU:aortal.ncdenr.org/web/lr/stormwater 8 J Email correspondence to and from this address is subject to the North Carolina Public Records Law and may be disclosed to third parties.